Regional ecosystem details for 5.9.2
| Regional ecosystem | 5.9.2 |
|---|---|
| Vegetation Management Act class | Least concern |
| Wetlands | Not a Wetland |
| Biodiversity status | No concern at present |
| Subregion | 4, 6, 2, (4.4), (1), (5), (4.5), (6.10), (3), (7), (9), (4.1) |
| Estimated extent1 | Pre-clearing 664000 ha; Remnant 2021 645000 ha |
| Short description | Senna artemisioides subsp. helmsii +/- Senna artemisioides subsp. oligophylla +/- Acacia georginae +/- Acacia spp. open shrubland on Cambrian limestone |
| Structure code | Open Shrubland |
| Description | Senna artemisioides subsp. helmsii +/-Senna artemisioides subsp. oligophylla +/- Acacia georginae +/- Acacia spp. open shrubland. Other low shrubs are frequently present. Scattered emergent low trees may be present in places. The ground layer is usually sparse to open, and dominated by Aristida spp., Enneapogon spp., Salsola australis, and a variety of forbs. In gilgai, Astrebla pectinata, Chrysopogon fallax and Eulalia aurea may be abundant. Occurs on flat to gently undulating tableland tops and footslopes of Cambrian limestone residuals. Soils predominantly shallow, red, calcareous loams and earths with limestone fragments in profile and on surface. Not a Wetland. (BVG1M: 24b). Vegetation communities in this regional ecosystem include: 5.9.2x1: Acacia cambagei predominates and forms a distinct but discontinuous canopy. Other trees and shrubs are very sparse, except for young Acacia cambagei, which is dense in most areas. The ground layer is open and variable, with Eragrostis xerophila and Sporobolus actinocladus common and a range of forbs including Sclerolaena spp., Abutilon fraseri, Boerhavia spp., Hibiscus brachysiphonius and *Portulaca oleracea. In many areas, 80-90% of low trees stand dead, but dense Acacia cambagei regeneration usually present. Occurs on fresh Cretaceous sediments on undulating plains. Soils shallow to moderately deep, stony red clays or desert loams, with surface ironstone or silcrete gravel. Not a Wetland. (BVG1M: 26a). 5.9.2x2: Acacia cambagei low open woodland. Other trees and shrubs are very sparse but may include Santalum lanceolatum and Eremophila mitchellii. Scattered shrubs may be present, including Senna spp. and Eremophila spp. The ground layer is variable, with Astrebla pectinata common. Occurs on superficial Cainozoic clay deposits on undulating plains. Soils shallow to moderately deep, stony red clays or desert loams, with surface ironstone or silcrete gravel. Weak Gilgai development occurs. Not a Wetland. (BVG1M: 26a). 5.9.2x3: Acacia cambagei low open woodland. Other trees and shrubs are very sparse but may include Santalum lanceolatum and Eremophila mitchellii. Scattered shrubs may be present, including Senna spp. and Eremophila spp. The ground layer is variable, with Astrebla pectinata and Sclerolaena spp. common. Occurs on Tertiary and Pleistocene alluvium and areas where sandy red earths overly clay/alluvia, moderately deep to deep, acidic, sandy red earths and sandy light clays. Not a Wetland. (BVG1M: 26a). |
| Supplementary description | Neldner (1991), 33 (52); Wilson and Purdie (1990a), R3 (29), R5 (34) |
| Protected areas | Diamantina NP, Bladensburg NP, Pullen Pullen SWR, Lochern NP, Lark Quarry CP |
| Special values | 5.9.2: Habitat for threatened plant species including Eremophila tetraptera. 5.9.2x1: Habitat for threatened plant species including Eremophila tetraptera. |
| Fire management guidelines | SEASON: Various (storm season / wet season or winter). INTENSITY: Low. INTERVAL: Fire return interval not relevant. INTERVAL_MIN: 100. INTERVAL_MAX: 100. STRATEGY: Aim to exclude fire by fuel reduction in adjacent vegetation communities where possible. Undertake partial burns when necessary to reduce fuel loads and protect against severe wildfire. Burn with high soil moisture (i.e., after rain/storms). ISSUES: The presence of a mixture of fire-tolerant resprouters (Senna artemisioides and Acacia tetragonophylla) and fire-sensitive seeders (e.g., Acacia georginae and Dodonaea microzyga) suggest low - moderate intensity fire could be used to protect the fire-sensitive species where necessary while retaining the integrity of the shrub layer. There is rarely enough fuel load to burn in any case. x1: Gidgee germinates infrequently following high rainfall events, mature slowly and are long-lived. These Acacias are vulnerable to frequent and high-severity fires which are unlikely when ground vegetation is sparse. Long absence of fire can result in canopy closure by Acacias and lead to self-protection of these communities. |
| Comments | 5.9.2: Many Acacia georginae tall shrubs stand dead with little regeneration present. 5.9.2x1: RE 5.7.7 and 5.7.7x1 were amalgamated into this RE. Many Acacia cambagei tall shrubs stand dead with little regeneration present. 5.9.2x2: Created to differentiate Cainozoic residual and colluvial clays (Landzone 4) from in situ clays (Landzone 9). These Cainozoic clays have a weak potassic signature indicating either leaching of potassium during deep weathering or mixing with leached material during transport, as opposed to fresh Cretaceous clays which retain a strong Potassic signature. 5.9.2x3: Created to differentiate Quaternary deposits (Landzone 5), from in situ clays (Landzone 9) and Cainozoic residual and colluvial clays (Landzone 4). |
1 Estimated extent is from version 13 pre-clearing and 2021 remnant regional ecosystem mapping. Figures are rounded for simplicity. For more precise estimates, including breakdowns by tenure and other themes see remnant vegetation in Queensland.
